Lysosomal storage disorders (LSD's) are a group of diseases resulting from the abnormal metabolism of various substrates, including glycosphingolipids, glycogen, mucopolysaccharides and glycoproteins. The metabolism of exo—and endogenous high molecular weight compounds normally occurs in the lysosomes, and the process is normally regulated in a stepwise process by degradation enzymes. For example, the enzymes beta-glucocerebrosidase and alpha-galactosidase are involved in the catabolism of glycosphingolipids.
A deficient activity in even one catabolic enzyme may impair the process, resulting in an accumulation of particular substrates. As part of lysosomal processing, the enzyme beta-glucocerebrosidase (referred to interchangeably herein as “GCase” or “Gcc”) cleaves the terminal glucose residue from glucosylceramide. A deficiency in GCase—in the form of one or more amino acid mutations—results in the LSD known as Gaucher disease. In Gaucher disease, various forms of mutant GCase have reduced, little, or no glucosylceramide cleavage activity, depending upon the mutated amino acid or amino acids. The severity of this disorder is correlated with relative levels of residual enzyme activity and the resulting extent of accumulation of the substrate.
Currently, Gaucher patients are treated using an expensive enzyme replacement therapy at a cost of about $300,000 USD per year per patient, or by using non-specific substrate reduction therapy. With these treatments, the enzyme deficiency itself is not treated, but rather, the accumulation of substrate is treated by reducing the synthetic levels of all gangliosides.
What is needed is an efficient and less-expensive way to treat individuals having Gaucher disease. The present invention addresses and meets this need.
Bromhexine, and its metabolite ambroxol, are expectoration improvers and mucolytic agents used in the treatment of respiratory disorders associated with viscid or excessive mucus. They work to decrease mucus viscosity by altering its structure. Neither bromhexine or ambroxol have been known to have any activity relevant to the treatment of lysosomal storage disorders.